It is known that, on board an aircraft, it is necessary to have hot air available to perform certain functions, such as air conditioning in the cockpit and the passenger cabin or for deicing certain parts of the aircraft.
It is also known that this hot air is taken from the turbine engines of the aircraft and has to be cooled significantly before it can be used. To do this, a heat exchanger is provided, this generally being known as a precooler, in which the hot air bled from the central generator of the turbojet engine is cooled by cold air bled from the fan duct, that is to say from the cold stream of the turbine engine. Such a precooler is generally housed in said fan duct, and this generates aerodynamic disturbances in said cold stream of the turbine engine.
What is more, the cold air bled from the cold stream of the turbine engine and used to cool the hot stream bled from the central generator gives rise to a current of heated cold air, which has to be discharged to the outside of the turbine engine, thus increasing the drag of the aircraft.